Daily Players’ Satisfaction with Pitching Performance Could Predict Shoulder and Elbow Injuries in High-school Baseball Pitchers: A Prospective Time-to-event Study

ABSTRACT Hypothesis and Background The relationship between baseball pitchers' satisfaction with their performance and the incidence of shoulder and elbow injuries is unclear. We hypothesized that self-evaluated satisfaction with pitching performance before an injury and incidence of shoulder and elbow injuries are related. Methods Baseline data on baseball experience, height, weight, elbow and shoulder range of motion, and shoulder muscle strength of high-school baseball pitchers were collected. During the season, all participants completed a self-recorded questionnaire regarding satisfaction scores, presence of shoulder and/or elbow pain, and pitching limitations due to shoulder and/or elbow pain experienced daily to determine when injuries occurred and record the satisfaction scores. The optimal satisfaction score cutoff value was determined through receiver operating characteristic (ROC) curve analysis; participants were categorized into satisfied and unsatisfied groups. Statistical tests were performed to evaluate the differences between the groups, obtain the time-to-event curves, and calculate the hazard ratios for the incidence of injury. Results Overall, 108 participants aged 15–17 years were enrolled and divided into satisfied (88) and unsatisfied (20) groups. The injury incidence rate was 10.2% and 50.0% in the satisfied and unsatisfied groups, respectively. High-school baseball pitchers with low satisfaction had a significantly increased risk of shoulder and elbow injuries; these players had a 7.3-times greater risk of injuries and 1.9-times earlier occurrence of injuries than pitchers who were satisfied with their performance. Conclusion Daily evaluation of players' self-satisfaction could predict shoulder and elbow injuries in high-school baseball pitchers.